This is very odd. Yes, my uname -r is B.11.00.

What is the first line of your script? I have:
#! /usr/bin/ksh

Could you post the results of a
ls -ln script
or whatever you called your script. And a
id -u

The numeric uids control access. If your current uid as displayed by "id -u" is not zero or equal to numeric uid that owns the script you should not be able to run it.

Unless the interpreter itself is suid to either root or the owner of the script. My ksh is 555.